Sprint planning is as much an art as much it is a science. And like all things , you get better at it with every passing sprint, as you start to develop a textured understanding of your team’s capacity, motivations, project scope etc.
Although there is no replacement for hand’s on past experience of planning and reviewing a completed sprint, but there are few thing which you should keep in mind :
Although the the duration of sprint varies from team to team and project to project, but from what we found out while studying top agile teams is that they tend to keep the duration of sprint as 15 days. Two weeks is the most common duration of sprints in software development and IT companies. Agile and scrum is about getting faster feedback and making sprints longer than 2 weeks defeats the whole purpose. In any case, you shouldn’t keep the duration more than 4 weeks. It is a fact that high performance teams need some positive pressure to get work done in an efficient manner, so shorter sprints really are ideal.
Your team has given its 100% for completing the sprint which might have included some ‘sprint cramming’ wherein everybody worked over time to get issues completed. So after such a run, it is important to keep a cool down time for few days for everybody to reflect upon the sprint and also to relax a little. Your team’s efficiency will go down significantly if you don’t keep this cool down time and there is very high probability that they might get burned out.
It is important to get everybody onboard with your plan of the sprint. You should listen to all of your team’s feedback and point of views before finalising the plan because if some of the members don’t fully agree with the plan then it might cause some unnecessary friction and lack of motivation to achieve the sprint goal.
You should know your team’s capacity in terms of how many user stories of how many story points they are capable to achieve in the given time frame. For this you can look at the previous sprint data such as sprint velocity , sprint burndown and release burdowns to come up with an ideal target.
It is important for you to remind your team about the bigger picture and how the current sprint’s goal aligns with the bigger goal, which the organisation is looking to achieve. It will help your team to get a good context and develop empathy towards the work which will in turn translate to higher levels of motivation and energy.
So sprint planning requires meticulous planning and an innate ability to adapt according to unforeseen situations and that is what the spirit of agile is.